Skip Links

USGS - science for a changing world

Scientific Investigations Report 2013–5231

Geochemical Investigation of the Hydrothermal System on Akutan Island, Alaska, July 2012

By Deborah Bergfeld, Jennifer L. Lewicki, William C. Evans, Andrew G. Hunt, Kinga Revesz, and Mark Huebner

Thumbnail of and link to report PDF (1 MB)Abstract

We have studied the geochemistry of the hot springs on Akutan Island in detail for the first time since the early 1980s. Springs in four discrete groups (A-D) along Hot Springs Creek showed generally higher temperatures and substantially higher Na, Ca, and Cl concentrations than previously reported, and total hot-spring discharge has also increased markedly. The springs now account for a heat output of ~29 MW, about an order of magnitude more than in 1981. Gas samples from the hot springs and from a fumarolic area on the flank of Akutan Volcano show high 3He/4He ratios (>6.4 RA) after correction for air contamination and reveal a common magmatic heat source. Hot-spring gases are unusually rich in N2, Ar, and CH4, suggesting that the water has boiled and lost CO2 during upflow beneath the flank fumarole field. Gas geothermometry calculations applied to the flank fumarole field implies temperatures of 200–240 °C for the reservoir, and Na-K-Ca geothermometry implies temperatures near 180 °C for the outflow waters that feed the hot springs. The results of our study confirm the existence of a substantial geothermal resource on the island.

First posted January 9, 2014

For additional information, contact:
Contact Information
Volcano Science Center - Menlo Park
U.S. Geological Survey
345 Middlefield Road, MS 910
Menlo Park, CA 94025
http://volcanoes.usgs.gov/
Akutan Peak Web site

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Bergfeld, D., Lewicki, J.L., Evans, W.C., Hunt, A.G., Revesz, K., and Huebner, M., 2014, Geochemical investigation of the hydrothermal system on Akutan Island, Alaska, July 2012: U.S. Geological Survey Scientific Investigations Report 2013–5231, 20 p., http://dx.doi.org/10.3133/sir20135231.

ISSN 2328-0328 (online)



Contents

Abstract

Introduction

Methods

Site Descriptions

Results

Discussion

Summary

Acknowledgments

References Cited


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/sir/2013/5231/
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Wednesday, January 08, 2014, 03:25:36 PM